The Differential Moderating Effect of Executive Compensation on Innovation Investment and Cash Holding Value in China

In the context of technological innovation promoting the long-term sustainable development of enterprises, how to better motivate senior executives to create greater value for an enterprise is being widely discussed. In particular, the COVID-19 outbreak has raised concerns about whether companies can deliver more value by holding large amounts of cash. However, although scholars have conducted a lot of research on topics such as innovation and frm value, how diferentiated executive compensation incentives regulate the relationship between frm innovation and the value of cash holdings has hardly been explored. Tis paper selects the balanced panel data of 1470 A-share listed companies from 2012 to 2020 in China to explore the relationship between innovation investment, executive compensation, and the value of cash holdings. It is found that innovation investment has a positive impact on the value of the cash holdings. Based on Herzberg’s hygiene motivational factors, diferent types of executive compensation may have a hygiene efect or a motivational efect, which is diferent. As a result, the moderating efect of executive compensation on innovation investment and the value of cash holdings are signifcantly diferent. Executive equity compensation and in-service consumption are motivational attributes. Tey have a positive moderating efect on innovation investment and the value of cash holdings. Te moderating efect of executive monetary compensation on innovation investment and the value of cash holdings changes with the change in monetary compensation. When monetary compensation is lower than the threshold value, monetary compensation is refected as a hygiene attribute, so it has no signifcant positive moderating efect on innovation investment and the value of cash holdings. When monetary compensation is higher than the threshold value, monetary compensation is refected as a motivational attribute, so it has a signifcant positive moderating efect on innovation investment and the value of cash holdings. Meanwhile, it is tested that monetary compensation is not manipulated by executive compensation defense behavior when it is refected as motivational attributes.


Introduction
In the post-fnancial crisis era, especially with the spread of COVID-19 in 2019 and the crisis of a number of US banks in 2023, we can see that the concept of "cash is king" is increasingly pursued by company managers. Local fnancial development is an important driving factor for corporate cash holding policies [1]. Additional cash holdings are more valuable for companies with severe fnancial strains or low existing liabilities [2]. Meanwhile, it will lead to a high level of cash holdings [3]. As shown in Figure 1, from 2012 to 2021 (data come from the CSMAR database), the average proportion of cash assets in the total assets of listed companies in Shanghai and Shenzhen stock exchanges exceeds 15% every year. Moreover, since the outbreak of COVID-19 in 2019, the proportion of corporate cash holdings has shown an obvious upward trend, and the large amount of corporate cash holdings has made scholars more interested in corporate cash holdings. Te large amount of corporate cash holdings makes scholars more interested in them. Although cash assets are highly liquid, their proftability is poor. Holding a large amount of cash is a waste of corporate resources, but why do companies still hold a large proportion of cash? Facing the phenomenon of large amounts of cash holdings, "the mystery of the value of cash holdings" is worth exploring deeply. How can large cash holdings better generate profts for the company and increase the value of cash holdings?
Innovation is an important source for enterprises to maintain competitive advantages [2], as well as the soul of sustainable development of enterprises. Investment is an efective means for companies to realize value increments, so innovation investment should have the same role, that is to say, innovation is of great signifcance to corporate value. If we can fnd an efective meeting point between innovation and the value of cash holdings, we will fnd an efective path to enhance corporate value. Both innovation investment and cash holding behavior are the results of executive decisions, so the important role of executive behavior should be considered when studying the relationship between innovation investment and the value of cash holdings.
In the context of globalization, executive compensation increases rapidly [4]. However, it is a pity that the existing scholars have not gone deep enough into corporate innovation, executive behavior, and the value of cash holdings. Te gaps in the present literature are mainly refected in several aspects.
(1) Executive compensation is only divided into monetary compensation, equity compensation, etc., according to the form of executive compensation, but there is no in-depth analysis of the attributes of diferent types of compensation. Terefore, the conclusion is simple. For example, scholars have found that the executive compensation gap will increase the value of cash holdings of enterprises [5]. Of course, analyzing the attributes behind diferent types of executive pay is not easy. Tis is directly related to the direction and perspective of research. Fortunately, this study fnds a suitable perspective for the classifcation of attributes of diferent types of executive compensation from the hygiene motivational factors theory proposed by Herzberg.
(2) Scholars have only conducted one-sided studies on the relationship between enterprise innovation, executive compensation, and the value of cash holdings. It is a pity that the existing scholars have not included the executive, corporate innovation and the value of cash holdings into a research framework. Te reasons are as follows. On the one hand, there are many research perspectives on enterprise innovation, and scholars have not conducted in-depth discussion on the relationship between executive compensation, enterprise innovation, and the value of cash holdings. On the other hand, their relationship may change under diferent background conditions, and scholars have not found a more appropriate perspective and theoretical support to explain and analyze the relationship between them. Terefore, this study takes executive compensation incentive as the link between innovation and the value of cash holdings and in-depth analyzes the moderating efects of diferent executive compensation types on innovation and the value of cash holdings. At the same time, in order to make the theoretical basis of this research more sufcient, we carry out the research based on the speculative perspective of Herzberg's hygiene motivational factors theory, to ensure that this research is more scientifc and widely applied.
According to the hygiene motivational factors theory, the factors causing executives' work motivation can be divided into incentive factors and motivational factors. Te hygiene motivational factors proposed by Herzberg divide the factors causing executive motivation into motivational factors and hygiene factors. Motivational factors can bring satisfaction to executives and motivate them to improve their work efciency. Hygiene factors do not give executives satisfaction or motivate them to perform their duties. When executive compensation plays diferent efects, the moderating efects on innovation investment and the value of cash holdings should be diferent. From the perspective of hygiene motivational factors, it can accurately distinguish the diferential moderating efect of diferent types of executive compensation on innovation investment and the value of cash holdings, further study the mechanism of action, and fnd out ways to enhance the value of cash holdings more efectively.
Te innovation and marginal contribution of the study are mainly refected in the following aspects.
Firstly, from the perspective of hygiene motivational factors, this paper creatively proposed and tested executive compensation including hygiene factors and motivational factors. At the same time, the paper empirically tests the diferential moderating efect of diferent types of executive compensation on innovation investment and the value of cash holdings, providing new development directions and empirical evidence for the development of hygiene motivational factors. Secondly, the paper tested the moderating efect of executive monetary compensation on innovation investment, and the value of cash holdings changes with the change in monetary compensation. When monetary compensation is lower than the threshold value, monetary compensation is refected as a hygiene attribute, so it has no signifcant positive moderating efect on innovation investment and the value of cash holdings. When monetary compensation is higher than the threshold value, monetary compensation is refected as a motivational attribute, so it has a signifcant positive moderating efect on innovation investment and the value of cash holdings.
Tirdly, the paper explored the diferential moderating efect of executive compensation on innovation investment and the value of cash holdings, providing theoretical support for improving corporate compensation design, and it provides ideas for enterprise value creation and long-term healthy development.
Te organizational structure of this paper is as follows. Section 2 gives the theoretical analysis and research hypothesis. Section 3 introduces research design and describes the related variables. Section 4 is empirical analysis. Section 5 is the robustness test. Section 6 is further research. Section 7 summarizes the basic fndings and insights of this study.

Innovative Investment and the Value of Cash Holdings.
Te study of cash holding motivation further started scholars' enthusiasm for studying corporate cash assets [6]. On the one hand, scholars conducted research on the infuencing factors of corporate cash holdings with the goal of optimal cash holdings. Some scholars studied how companies adjust their cash holdings through media reports [7] and whether female representation on the board of directors helps companies to obtain the best cash holdings [8].
On the other hand, they focused on exploring the value efect of corporate cash holdings. Scholars believe that, on the premise of an efcient capital market, the market valuation of corporate cash is the market value of corporate cash. A discount occurs when the market value of the company's cash is below its book price. Faulkender and Wang [9] studied non-fnancial listed companies in the United States and found that the marginal cash value of $1 of the company was $0.94. Naikang and Jinju [10] found that the market value of listed companies' cash assets of ¥1 is only ¥0.5-¥0.6 by measuring the marginal value of cash of listed companies in China, so the discount problem is more serious. Based on diferent research samples, several scholars have concluded that the cash held by companies is discounted, and the degree of a cash discount of Chinese companies is more serious than that of companies from other countries. From the perspective of the market, the capital market in China has a late start and is not perfect, so the transmission efciency of the cash value is low. From the perspective of the efciency of cash, listed companies in China do not fully play the value of cash, so the problem of discounts is more serious.
Levels of forward-looking information disclosure [11], fnancial hedging [12], tax evasion [13,14], corporate social responsibility fulfllment [15,16], and product market competition [17][18][19] can improve the value of the company's cash holdings. Corporate cross-listing [20], related-party transactions [21], insider equity pledges [22], and corporate internationalization characteristics [23] will reduce the value of cash holding. Compared with non-state-owned enterprises, the value of cash holdings in state-owned enterprises is lower [24,25], and enhancing the separation of the two rights of state-owned enterprises will lead to a lower value of cash holdings [13]. In particular, when the CEO of state-owned enterprises gets political promotion [26] or the separation of two powers increases [27], the value of cash holdings will be lower. Meanwhile, fnancing constraints have a strengthening efect on the value of cash holdings in non-state-owned companies, while the efect is not significant in state-owned companies [19]. In addition, audit pricing [28], corporate uncertainty [29], types of institutional investors [30], the macroeconomic environment [31,32], and corporate governance environment [17,33,34] will have a signifcant impact on the value of cash holdings.
When companies measure the benefts and costs of cash holdings, the investment motivation in cash holding motivation theory just provides the possibility for cash holdings to bring benefts. When companies face more investment opportunities, holding cash can avoid fnancial difculties [35]. Terefore, the mechanism of innovation investment with the value of cash holdings is analyzed from the following perspectives.
Innovative investments bring benefts to the company and enhance its cash value. Innovation is the inexhaustible driving force for the long-term development of the company, and holding cash is conducive to grasping good innovation investment opportunities. Te transformation of innovation achievements has won competitive advantages for the company, and the value of cash holdings has been improved. Especially when the industry competition is very intense, good investment opportunities are essential for enterprises. When innovation investment is successful, it will bring abundant profts for enterprises. Te continuous rise of corporate profts will enable enterprises to have better market performance, and the value efect of cash holdings will be more apparent.
Innovation investment can reduce a company's free cash fow. According to the free cash fow hypothesis, the high level of cash holdings increases the competition between executives and shareholders for control of company resources. As a result, the agency problem will become more serious and hurt the company's value. Innovation investment transforms the company's free cash into reserve investment funds, limits the scale of free cash fow, reduces the loss caused by internal friction, and improves the efciency of the value of cash holdings.
Innovation investment sends a signal to the public about the company's long-term development. According to the signal transmission theory, the improvement of innovation investment level conveys to the public investors that the company has strong research and development ability, Discrete Dynamics in Nature and Society abundant fnancial support, and better development prospects. Innovation investment can signifcantly increase a company's share price [36]. An increase in the company's stock price improves the confdence of public investors and is conducive to the further improvement of the company's value.
Holding cash is conducive to the improvement of enterprise R&D investment. Enterprise innovation investment is the recombination of production factors and production conditions. It will change the investment proportion of each factor inside the enterprise, which is conducive to improving the efciency of enterprise resource allocation. In addition, innovation investment may involve important business secrets of enterprises, which should be kept secret by enterprises. Terefore, external fnancing constraints are relatively large, and enterprises can only rely on their own funds to fll the R&D gap. Some scholars have found that equity fnancing is negatively correlated with corporate performance [37]. Holding cash not only reduces the cost of external fnancings, such as equity fnancing, but also boosts investment, especially in research and development [38]. Terefore, from the perspective of fnancing order theory, cash held by companies is used for innovation investment with low cost, so the cost will reduce and the value of innovation investment will improve. In view of this, the following hypothesis is proposed.

Te Moderating Efect of Executive Compensation on Innovation Investment and the Value of Cash Holdings under the Background of Hygiene Motivational Factors.
Te hygiene motivational factors theory holds that only motivational factors can bring satisfaction, while hygiene factors can only eliminate dissatisfaction, but not bring satisfaction. Te improvement of motivational factors can better promote employees' work enthusiasm and improve work efciency. Te satisfaction of hygiene factors can only eliminate the dissatisfaction of employees but cannot stimulate the enthusiasm of employees, so it cannot promote the improvement of work efciency. Te hygiene motivational factors established Herzberg's important position in the feld of motivation theory. Scholars have been continuously verifying and developing the hygiene motivational factors and enriching the relevant theoretical system. With the development of the motivation theory system, scholars have included teamwork [39], interest, and reputation motivation [40] into motivation factors.
However, some scholars have found that it is impossible to classify work characteristics by dichotomy [41]. Motivation factors do not bring greater job satisfaction than hygiene factors [42]. For this reason, Herzberg conducted a supplementary experiment to verify the stability of the conclusion of the hygiene motivational factors by expanding the investigation scope and enriching the investigation objects and supplementary investigation content [43]. Although scholars have diferent opinions on the hygiene motivational factors, it is undeniable that the hygiene motivational factors have strong application value in reality. Of course, maintaining critical thinking and exploring the hygiene motivational factors critically is an important driving force for academic progress.
Herzberg mentioned that hygiene factors and motivational factors are not completely opposite, and a certain incentive method may cover two factors. However, there are essential diferences between hygiene factors and motivational factors. Te motivational efect of the hygiene factor is not obvious, and the hygiene efect of motivational factors is also poor. Due to the diferences in the social development stage and national conditions between China and other countries, there will be diferences in whether the same incentive method is a motivating factor or a hygiene factor [44]. Herzberg thinks salary and bonus are hygiene factors. However, with the development of compensation design, equity compensation and in-service consumption have become an important part of executive compensation incentives. Equity compensation and in-service consumption are often related to work content. Equity compensation can motivate executives to work hard for the long-term interests of the company, which has a signifcant motivational factor attribute. In-service consumption is regarded as an invisible salary, which has greater uncertainty. When the company's performance is good, company executives are more likely to enjoy more ofce, travel, tourism, and other opportunities, so in-service consumption is highly correlated with the company's performance. In particular, with the increasingly strict salary control, in-service consumption has become an alternative for corporate executives to pursue high salaries [45]. Terefore, in-service consumption also has obvious motivational factors. Executive monetary compensation includes not only the salary and bonus of the company's executives but also the monetary compensation obtained in other forms. Te compensation beyond salary and bonus is closely related to the value which executives can create for the enterprise, playing a motivational role that hygiene factors cannot complete, so it should have the attribute of motivational factors.
Terefore, from the perspective of adapting to the development requirements of the new era, the equity compensation and in-service consumption of corporate executives are motivational factors, while the monetary compensation includes hygiene factors as well as motivational factors.
Te inverted position of executive compensation will inhibit the input and output of innovation [46]. Good corporate governance can improve the value of cash holdings in the company, and investors will give the company a higher cash pricing [47]. Te monetary compensation of senior executives can efectively promote the R&D investment of enterprises, but the promotion efect of equity compensation is not obvious [48]. Some scholars have found that the characteristics of stakeholder networks are closely related to open innovation performance [49]. In particular, venture capital institutions promote open innovation by strengthening executive compensation incentives in the company [50]. Te research of scholars also refects the important role that executive behavior can play in the relationship between innovation investment and the value of cash holdings. Because of the principal-agent confict, the self-interested behaviors of managers are not conducive to the positive promotion efect of innovation investment on the value of cash holdings. As a widely recognized internal governance mechanism, executive compensation contract plays an important role in reducing agency costs. It is also possible that executive compensation can play an important moderating efect on the mechanism of innovation investment and the value of cash holdings.
From the perspective of increasing income, the transformation of innovation investment into enterprise value is inseparable from the efective management of senior executives. Te conversion cost of corporate cash into executive private income is lower than that of other assets. Holding cash provides opportunities for the self-interested behavior of executives and limits the realization of the value of the company's cash holdings. Executive compensation with motivative attributes can efectively reduce the moral hazard of senior executives, encourage senior executives to concentrate on their work, and promote the convergence of senior executives' personal goals and corporate goals. Finally, the results of innovation investment bring the realization of enterprise value.
From the perspective of reducing free cash fow, the manipulation cost of cash is low, and corporate executives may manipulate the company's cash to build a "personal empire" and damage the value of the company [9]. By manipulating the free cash fow right, senior executives infuence the increase of the value of cash holdings. Te efective executive compensation mechanism reduces the agency cost of the company and can reduce the executive's control of free cash fow. Executive compensation with motivational attributes can efectively correct the negative impact of free cash fow.
From the perspective of signal transmission, in the context of the state's encouragement of technological innovation, executive compensation with motivative attributes encourages senior executives to devote themselves to technological research and development, so as to establish a positive social image for enterprises. At the same time, it also indicates that the enterprise has strong scientifc research ability and market competitiveness, and the comprehensive strength is strong, which is conducive to the further improvement of the market value of the enterprise. On the contrary, due to information asymmetry, senior executives can manipulate the investment behavior of the enterprise, which will lead to the depreciation of the value of the company regardless of over-investment or underinvestment. Executive compensation with motivative attributes also plays a normative role in the investment behaviors of corporate executives, constrains bad investment behaviors, improves corporate investment efciency, and reduces cash wastage.
Based on the above analysis, diferent types of executive compensation have diferent attributes. It could be a motivational attribute or a hygiene attribute. When executive compensation plays a motivational attribute, it can efectively promote corporate earnings brought by innovation investment, reduce free cash fow, and better convey positive signals for enterprises. Terefore, it has a signifcant positive moderating efect on the mechanism of innovation investment and the value of cash holdings. Te research model of this study is shown in Figure 2. Based on the above analysis, the following hypothesis is proposed.
Hypothesis 2. (H2) If executive compensation plays a motivational role, it has a signifcant positive moderating efect on innovation investment and the value of cash holdings.  4) Exclude enterprises with an asset-liability ratio greater than 1 or less than 0. Audit fees, executive compensation, and other corporate fnancial data are derived from the CSMAR database, and enterprise innovation data are derived from the Wind database. Since innovation behavior is obviously long-term and sustainable, in order to ensure scientifc research, we should choose to balance panel data for research. Terefore, companies that were delisted or newly listed during the study period were deleted. In order to ensure the validity of the data, all sample data (1%, 99%) were tailed, and fnally, 10320 balanced panel data of 1470 listed companies were obtained. Tis paper mainly uses Stata 16.0 to process and analyze the data.

Model Construction and Variable Defnition.
Referring to the research method of Faulkender and Wang [9], the change in stock price caused by the change in the company's cash assets is used to measure the value of the cash holdings, that is, the infuence of the change of cash holdings on the excess return rate of stock is used to measure the value of the cash holdings, and model (1) is constructed. In model (1), α 1 represents the infuence of the change in the company's cash holdings on the excess return rate of the company's stock. When α 1 > 0, it indicates that the change of cash has a positive impact on the value of the cash holdings, that is, the greater the change in the company's cash, the greater the value of the cash holdings. To measure the impact of innovation investment on the value of cash holdings, the proxy variable of innovation investment is introduced. Referring to the research of most scholars, the innovation investment level is measured by the ratio of the company's R&D expenditure to its operating revenue [51], and a higher ratio indicates a higher level of investment in innovation. When α 10 > 0, it indicates that innovation investment has Discrete Dynamics in Nature and Society 5 a positive impact on the value of cash holdings. When α 10 < 0, it indicates that innovation investment has a negative impact on the value of cash holdings. (1) In order to explore the moderating efect of executive compensation between innovation investment and the value of cash holdings, the cross-multiplier term including executive compensation incentive is introduced to establish model (2). In model (2), executive compensation is shown by executive monetary compensation (MC), equity compensation (EC), and in-service consumption (CC), respectively. Te monetary compensation is measured by the natural logarithm of the total compensation of the top three executives [52]. Equity compensation is measured by the shareholding ratio of executives [53]; in-service consumption is measured by the ratio of administrative expenses to operating income [54]. When β 13 > 0, it indicates that executive compensation has a positive moderating efect. When β 13 < 0, it indicates that executive compensation has a negative moderating efect.
In order to reduce the impact of heteroscedasticity on the model, this paper conducted logarithmic processing on the variables with large values and divided each variable by the initial market value of the company to reduce the impact of the company size on the model. If the variable in the model is preceded by ∆, it is the change of the value of the variable in the current period and the previous period.
Te defnition of the main variables in the model is shown in Table 1. Te measurement of interest expense refers to the study of Baohong and Danting [55] and is shown by fnancial expense. Te measurement of a company's market value refers to the research of Xudong et al. [56] and is measured by the product of the total number of shares issued by a company and the annual closing price.       companies is obvious. Te minimum shareholding ratio of senior executives is 0, indicating the year in which senior executives do not hold shares. Tere is a big diference between the maximum and minimum of the in-service consumption of senior executives, indicating that the resources they can enjoy are very diferent. Te maximum value of the asset-liability ratio is 0.862, and the minimum value is 0.069, indicating that the listed companies have great diferences in fnancial leverage and great diferences in fnancial risk, while the average value is 0.460, indicating that the overall leverage ratio of listed companies is not high. Te minimum value of innovation investment is 0, indicating that the company has no innovation investment year.

Analysis of Regression
Results. It can be seen from the regression results (Table 3) that α 1 in hypothesis (1) is 0.179, greater than 0, and signifcant at the 1% level, indicating that the change of cash of listed companies has a positive efect on the value of cash holdings in the company. Te coefcient of the cross-term (α 10 ) is 0.008, greater than 0, and is signifcant at the level of 5%, indicating that innovation investment has a positive impact on the value of cash holdings. Terefore, hypothesis (1) is proved. From the regression results of the moderating efect, the monetary compensation of executives has a positive moderating efect on the relationship between innovation investment and the value of cash holdings, but the efect is not signifcant, which needs further analysis.
104.725 * * * , * * , and * denote rejection of the test at 1%, 5%, and 10% level, respectively. Te moderating coefcients of equity compensation and in-service consumption are 0.010 and 0.007, respectively, greater than 0, and both are signifcant at the level of 5%. Tese results indicate that executive equity compensation and inservice consumption are motivational factors and have a signifcant positive moderating efect on the relationship between innovation investment and the value of cash holdings.

Instrumental Variable Method.
Te instrumental variable method was used to alleviate the possible endogenous problems in the model. Referring to the practice of scholars, the average value of industry and year innovation input is taken as the instrumental variable of innovation input to carry out two-stage regression. Te regression results are shown in Table 4.
In the frst stage regression, the instrumental variable and the replaced variable have a signifcant positive correlation. In the second stage regression, there is a positive correlation between instrumental variables and dependent variables, which is signifcant at the level of 1%. In the test of weak instrumental variables, the F value is 374.383, much higher than 10, and there is no problem with weak instrumental variables. Terefore, after considering the endogeneity of innovation investment, the positive correlation between innovation investment and the value of cash holdings is still signifcant.

Propensity Score Matching (PSM).
Using the propensity score matching method to test can reduce the endogeneity problem caused by the self-selection of samples. Enterprises with innovative investments in the current year shall be treated as the processing group. Enterprises that have not made innovation investments in the current year are regarded as the control group. Te results of the propensity score matching test are shown in Table 5. By using the nearest neighbor matching method for sample matching, the P values of other variables except Levi are signifcantly larger than 0.1, indicating a good matching efect. Te matched samples were used for regression, and the regression coefcient of the cross-product term was 0.008, which was signifcant at the level of 5%, indicating that the positive efect of innovation investment on cash holding value was still robust, excluding the impact of sample selfselection.

Substitution Variables.
Referring to the research methods of previous scholars, the ratio of R&D investment to total assets (Inv2) is taken as a substitute variable for enterprise innovation investment [57], and the robust regression results are shown in Table 6. Te coefcient of the cross-term between innovation investment and △Cash i,t / MV i,t−1 is positive and signifcant at the level of 1%, indicating that innovation investment has a positive efect on the value of cash holdings. Te cross coefcient of equity compensation of executives, innovation investment, and △Cash i,t /MV i,t−1 is 0.01, greater than 0, and signifcant at 5%, indicating that equity compensation of executives is a motivational factor and has a positive moderating efect on the relationship between innovation investment and the value of cash holdings. Te coefcient of in-service consumption, innovation investment, and △Cash i,t /MV i,t−1 is 0.006, greater than 0, and signifcant at 10%, indicating that in-service consumption of executives is a motivational factor and has a positive moderating efect on innovation investment and cash holding value. However, the coefcient of executive monetary compensation, innovation investment, and △Cash i,t / MV i,t−1 is 0.002, but not signifcant, indicating that the attribute of executive monetary compensation needs to be further verifed.

Analysis of Incentive Factors of Executive Monetary
Compensation Adjustment 6.1.1. Verifcation Method 1. Treshold regression analysis of the moderating efect of executive monetary compensation.
According to the above empirical results, it has been confrmed that executive equity compensation and inservice consumption both have a signifcant positive moderating efect on the relationship between innovation investment and the value of cash holdings, indicating that executive equity compensation and in-service consumption are motivational factors. However, the positive moderating efect of executive monetary compensation on innovation investment and the value of cash holdings is not signifcant.
Just as the above theoretical analysis, based on the hygiene motivational factors, in the monetary compensation of corporate executives, the salary and bonus have the attribute of a hygiene factor, while the compensation exceeding salary and bonus has the attribute of a motivational factor.
In order to verify the theoretical analysis conclusions, the threshold efect model is used to test the moderating efect of executive monetary compensation on the relationship between innovation investment and the value of cash holdings in stages. When the executive monetary compensation exceeds a certain threshold, the study examines whether the executive monetary compensation has the attribute of a motivational factor.
Terefore, the following hypothesis is proposed: when the executive monetary compensation is higher than a certain threshold, the motivational efect is refected, and it has a signifcant positive moderating efect on the relationship between innovation investment and the value of cash holdings.
In order to ensure the continuity and rigor of the research, the samples from the above studies continue to be used. 10320 balanced panel data from 1470 listed companies were selected for analysis and model (3) was established. q i,t (E i,t ) is the threshold variable; "c" is the threshold value; and "I" is an indicator function. Te indicator function "I" takes on the value 1 if the conditions in parentheses are met and 0 otherwise. Firstly, the signifcance level of the threshold efect was tested. Te threshold efect test results are shown in Table 7, and the threshold regression results are shown in the second column of Table 8. Te results of the double threshold model and triple threshold model were not signifcant, while the single threshold model passed the test of the threshold efect. It shows that there is a threshold efect of executive monetary compensation in the moderating effect of executive monetary compensation between innovation investment and the value of cash holdings. 12 Discrete Dynamics in Nature and Society (3) According to the regression results of the threshold model, the moderating efects of executive monetary compensation between innovation investment and the value of cash holdings are diferent under diferent levels of executive monetary compensation. In the frst interval of executive monetary compensation, λ 13 fails to pass the signifcance level test, indicating that when executive monetary compensation is lower than the threshold value, executive monetary compensation does not have the attribute of motivational factor and has no signifcant positive moderating efect on the relationship between innovation investment and the value of cash holdings. In the second interval, λ 14 is 0.022, which is greater than 0 and signifcant at the 1% level, indicating that when the executive monetary compensation is higher than the threshold, the executive monetary compensation has the property of motivational factor and has a signifcant positive moderating efect on the relationship between innovation investment and the value of cash holdings.

Verifcation Method 2. Moderating efect analysis of executive excess monetary compensation.
Te threshold regression model can be used to better test the interval diference of executive monetary compensation from the perspective of quantity. In order to more comprehensively test the diference of motivational factor attributes in diferent sections of executive monetary compensation, we can also start from the perspective of executive excess monetary compensation. Executive excess monetary compensation is part of executive monetary compensation above the normal level. Te part of executive monetary compensation above the normal level has little relationship with the executive's established salary and bonus, so it should not be a hygiene factor but should be a motivational factor. Terefore, if the executive monetary compensation is divided into excess executive monetary compensation and non-excess executive monetary compensation for a comparative study, the moderating efect of executive monetary compensation on the relationship between innovation investment and the value of cash holdings can be more clearly compared. Based on the hygiene motivational factors, if the executive compensation exceeding a certain threshold is refected as the incentive attribute, the positive moderating efect of executive excess monetary compensation between innovation investment and the value of cash holdings should be more signifcant than that of nonexcess executive compensation. Referring to the research of Mengjie and Zhinan [58], overpay is measured by the difference between the actual monetary compensation of the top three executives and the normal monetary compensation estimated by the compensation decision model.
In the model for estimating executive monetary compensation, factors such as company size (Size), return on assets (Roa), ratio of intangible assets to total assets (IA), and company registration place (Zone) are controlled (model 3). Meanwhile, a calculation model for executive excess monetary compensation (model 4) is constructed. Using the research samples in the above study, 10320 balanced panel data of 1470 listed companies were selected for the empirical test. Te test results are shown in Table 8. In the Inv � Inv1 group, the coefcient of the positive moderating efect of excess executive compensation is 0.018, which is signifcant at 5% level, far greater than the positive moderating efect of non-excess executive compensation between innovation investment and the value of cash holdings (the coefcient is 0.001), and the empirical P value is 0.020. Terefore, the positive moderating efect of excess executive monetary compensation on innovation investment and the value of cash holdings is signifcantly stronger than that of non-    14 Discrete Dynamics in Nature and Society excess executive monetary compensation on innovation investment and the value of cash holdings. In the Inv � Inv2 group, the coefcient of positive moderating efect of excess executive compensation on innovation investment and the value of cash holdings is signifcant at 0.020, which is signifcant at 1% level, far greater than the positive moderating efect of non-excess executive compensation on innovation investment and the value of cash holdings (−0.001), and the empirical P value is 0.010. Te empirical results both support the theoretical conclusion and prove the robustness of the conclusion.

Te Possibility Test of Compensation Defense in Executive
Monetary Compensation Adjustment. Based on the hygiene motivational factors, when executive monetary compensation is at a high level, it is refected as a motivational factor and has a signifcant positive moderating efect on the relationship between innovation investment and the value of cash holdings. However, it is necessary to consider whether the possibility of compensation defense exists when the higher level of executive monetary compensation plays a positive incentive role.
In the face of the external pressure of pay fairness, executives of listed companies have the need and motivation for compensation defense. At the same time, the executive is the commander of enterprise innovation behavior and cash holding, which provides the feasibility of executive compensation defense. Of course, the pressure of executive compensation defense is mainly related to enterprises' performance improvement, enterprise strategic deployment, and other areas of high social concern. However, in order to ensure the rigor of the study, the possibility of executive monetary compensation defense should be tested. Te pressure of compensation defense is diferent in diferent enterprises. In order to test whether executives have compensation defense behavior, it is necessary to analyze the diference in the adjustment efect of executive monetary compensation in diferent samples of enterprises.
Firstly, the executive compensation of state-owned enterprises is more likely to attract social attention and doubt. Terefore, when state-owned enterprises obtain excessive monetary compensation, they will be under greater external pressure, and the demand for compensation defense will be more obvious.
Secondly, if the increase in executive compensation is highly sensitive to the growth of corporate performance, that is, the increase of executive compensation is brought about by the growth of corporate performance, the public will have relatively few voices questioning the higher level of executive compensation. On the contrary, if the relationship between executive compensation and performance is not close, the public will raise doubts about the higher level of executive compensation and the pressure on executive compensation defense will increase signifcantly.
Tirdly, institutional investors have more professional advantages than ordinary investors. At the same time, institutional investors have a stronger ability to interpret executive compensation and better understand the value of the company, so the possibility of executive compensation defense is lower. Terefore, when the shareholding ratio of institutional investors is high, the possibility of compensation defense of senior executives is less. On the contrary, when the shareholding ratio of institutional investors is low, the possibility of compensation defense of senior ofcials is greater.
To summarize the above three points, if the enterprise is state-owned and executive monetary compensation has a strong positive moderating efect on the relationship between innovation investment and the value of cash holdings, it will indicate that executive compensation defense behavior afects the moderating efect of executive monetary compensation between innovation investment and the value of cash holdings. On the contrary, if the monetary compensation of executives has a weak positive moderating efect, it will indicate that the executive compensation defense behavior does not afect the relationship between innovation investment and the value of cash holdings.
If the sensitivity of compensation performance is low and executive monetary compensation has a strong positive moderating efect on the relationship between innovation investment and the value of cash holdings, it will indicate that executive compensation defense behavior afects the moderating efect of executive monetary compensation on the relationship between innovation investment and the value of cash holdings. On the contrary, if the monetary compensation of executives has a weak positive moderating efect, it will indicate that the executive compensation defense behavior does not afect the relationship between the innovation investment and the value of cash holdings.
If the proportion of institutional investors is high and the monetary compensation has a strong positive moderating efect on the relationship between innovation investment and the value of cash holdings, it will indicate that the executive compensation defense behavior afects the moderating efect on the relationship between the monetary compensation and the innovation investment and the value of cash holdings. On the contrary, if the monetary compensation of executives has a weak positive moderating efect, it will indicate that the executive compensation defense behavior does not afect the relationship between the innovation investment and the value of cash holdings. In order to study whether executive compensation defense behavior exists in the relationship between innovation investment and the value of cash holdings, the sample of excess executive monetary compensation in the above study will continue to be used for analysis, and model 2 will be used for regression analysis. Te empirical results are shown in Table 9.
Firstly, the samples are divided into state-owned enterprises and non-state-owned enterprises. In the non-stateowned enterprises, β 13 � 0.015 and is signifcant at 10% level. In the state-owned enterprises' sample, β 13 � 0.009, but not signifcant. Terefore, compared with non-state-owned enterprises, in state-owned enterprises, the positive moderating efect of executive compensation on the relationship between innovation investment and the value of cash holdings is not strong.
Secondly, referring to Kubo's method [59], the compensation performance sensitivity is calculated and the sample is divided into the group with high compensation performance sensitivity and the group with low compensation performance sensitivity by taking the median of compensation performance sensitivity as the dividing line. In the high-performance sensitivity sample, β 13 � 0.018 and is signifcant at 5% level. In the low-performance sensitivity sample, β 13 � 0.008, but not signifcant. Terefore, compared with enterprises with high compensation performance sensitivity, in enterprises with low compensation performance sensitivity, the positive moderating efect of executive compensation on the relationship between innovation investment and the value of cash holdings is not strong.
Tirdly, the sample is divided into the group with high institutional ownership and the group with low institutional ownership by taking the median institutional ownership as the boundary. In the sample with high institutional ownership, β 13 � 0.023 and was signifcant at 1% level, while in the sample with low institutional ownership, β 13 � 0.011, but not signifcant. Terefore, compared with enterprises with a low proportion of institutional investors, in enterprises with high proportions of institutional investors, the positive moderating efect of executive compensation on the relationship between innovation investment and the value of cash holdings is not strong.
In summary, the above test results do not meet the established conditions of the compensation defense hypothesis, indicating that the moderating efect of executive compensation on the relationship between innovation investment and the value of cash holdings is not afected by the compensation defense.

Discussion
Firstly, the most important innovation and research fndings of this study are the diferentiated moderating efects of diferent types of executive compensation incentives on corporate innovation and the value of cash holdings. In particular, the hygiene motivational factors theory is introduced, which makes the theoretical support of this study more solid. In China, monetary compensation incentive is the main way of executive incentive mechanism arrangement. Te study may provide important ideas for the structure of executive compensation. In contrast, monetary compensation can achieve the incentive attribute only after it exceeds the threshold value. In other words, most of the monetary compensation only plays the role of the hygiene attribute. Should enterprises try to appropriately increase the proportion of equity compensation and in-service consumption, so as to increase the incentive efect? Of course, scholars have found that companies with institutional investors holding both stocks and bonds are more willing to adopt a compensation structure with lower risk, that is, fewer stock options and more internal debt, which also indicates a higher risk of equity-based compensation [60]. Other scholars have found that monetary compensation is more likely to increase agency conficts, while equity compensation is more likely to decrease agency conficts [61]. A scientifc and reasonable executive compensation structure can efectively promote enterprise innovation [62]. Combined with the research results of many scholars, it can provide more ideas for enterprises to design the executive compensation system.
Secondly, it is necessary to rethink the problem of incentive compatibility. Based on the hygiene motivational factors theory, this study proposes the moderating efect of diferent executive compensation on the diferentiation of innovation investment and the value of cash holdings. Incentive compatibility must be addressed in order to prevent executives from neglecting innovation by focusing on shortterm performance. Some scholars have found that in the previous executive compensation arrangements of enterprises, executive compensation would be linked to performance, but it would lead to executives reducing the expenditure on innovation investment to meet the requirements of performance evaluation [63]. It is even possible to conduct earnings management behavior through innovation investment [64]. Because innovation investment is risky and has a long cycle, executives need to be mentally prepared to take risks for a long time and make sustained eforts. In order to make senior executives pay more attention to innovative activities rather than meet the shortterm performance assessment, enterprises should constantly strengthen the embodiment of innovation orientation in the design of executive compensation.
Tirdly, although theoretical analysis and empirical test results support that executive compensation can play a positive moderating role, in combination with reality, we have to seriously consider whether more executive compensation is more appropriate. On the one hand, Executive compensation can play motivating efects, but excessive executive compensation may bring other disadvantages. Senior executives are limited by their individual abilities, which make the incentives for senior executives to work continuously. In particular, the promulgation of the salary limit order shows that while thinking about the market efciency, we should give consideration to the market fairness. Fortunately, in further analysis, we do not fnd signifcant compensation defense behavior in the mechanism of executive compensation in innovation investment and cash holding value. But we still cannot guarantee that Discrete Dynamics in Nature and Society executive pay is not justifed in other areas. On the other hand, the increase in executive compensation can stimulate the incentive efect, but whether the incentive efect can last for a long time or whether there is a marginal diminishing efect between them, we can investigate it in future.
Fourthly, through the study of large sample data, we found that monetary compensation beyond the threshold value has an obvious motivational attribute, while monetary compensation within the threshold value has hygiene attribute. It is worth noting that the threshold value of monetary compensation will be afected by the industry and economic development period. Monetary compensation is greatly afected by the industries and regions [64]. Terefore, after the existence of the monetary compensation threshold has been proved, scholars should further explore the diference in the monetary compensation threshold of senior executives in diferent industries and regions. In practice, fnding the threshold value of monetary compensation in diferent industries can better guide diferent enterprises to set up monetary compensation structures.
Finally, although this study draws conclusions through normative analysis and empirical testing methods, there are still some shortcomings. (1) Although this study has refned the research on the categories of executive compensation, there is still room for exploration on the refnement of enterprise innovation. Technological innovation in enterprises takes a long time from R&D input to output. If we can separately describe the mechanism of diferent links of enterprise innovation investment (innovation input, innovation achievement transformation, innovation value output, etc.) and enterprise cash holding value, it will make the research more full and complete. (2) Te value of cash holdings is a marginal value. It is hard to measure exactly. Although this study has been empirically tested by referring to the measurement methods of previous scholars, it can ensure that the empirical results are consistent with those of previous scholars. However, it is still possible and necessary to explore a more scientifc way to measure the value of cash holdings. (3) Te objects of this study are mainly listed companies in China. Tis study enriches the economic research of developing countries. However, because the economic development level and institutional background of diferent countries and regions may be quite diferent, the research results may not be able to adapt to all diferent countries or regions.

Conclusions.
In the context of innovation-driven development strategy, the promotion of enterprise value through executive compensation incentives has been a widely discussed topic. Tere are also great diferences in the incentive efect of diferent types of executive compensation. Trough theoretical analysis and the empirical test, this study is shown as follows.
(1) Innovation investment has a positive promoting efect on the value of cash holdings. (2) Based on the hygiene motivational factors theory, executive equity compensation and in-service consumption both have positive moderating efects on innovation investment and the value of cash holdings. Tat is to say, executive equity compensation and in-service consumption show motivational efects on their relationships. (3) When the level of executive monetary compensation exceeds the threshold, executive monetary compensation has a positive moderating efect on the relationship between innovation investment and the value of cash holdings, so it has the attribute of a motivational factor and is not disturbed by executive compensation defense behavior.

Signifcance.
Te theoretical signifcance of this study is as follows.
Firstly, the application extension of the hygiene motivational factors theory is extended, which is also the most important innovation of this research. Tis study creatively divides executive compensation into two parts: hygiene attributes and motivational attributes. Especially for monetary compensation, this study found that monetary compensation at diferent levels has diferent incentive attributes. When executive compensation plays diferent incentive attributes, it has diferent moderating efects on enterprise innovation and the value of cash holdings. Tis also brings the hygiene motivational factors theory, innovation theory, and enterprise value theory into the unifed research framework and deepens the theoretical connection.
Secondly, the study enriches the theoretical research of cash value. Perhaps only studying the relationship between enterprise innovation behavior and enterprise value cannot become the focus of scholars; after all, the relevant research is relatively abundant. However, in the wake of the COVID-19 outbreak and the crisis at several US banks, companies are hoarding cash as a precaution. At this time, it is more important to study enterprise value from the perspective of cash. Innovation and enterprise value increment have always been important means for enterprises to pursue long-term sustainable development. At this time, it is more meaningful to enrich relevant theories.
Corresponding to the theoretical innovation signifcance, the practical signifcance of this research is equally important. Te practical signifcance of this study is as follows.
Firstly, the study confrms that there is a signifcant positive correlation between innovation investment and the value of cash holdings, indicating that increasing innovation is the right choice for enterprises to improve cash value, which provides practical guidance for enterprises to increase R&D arrangements.
Secondly, the study introduces the hygiene motivational factors theory into the research of executive compensation incentives. Because diferent types of executive compensation and even diferent levels of executive types play diferent incentive roles, this provides an important idea for enterprises to prudently arrange the compensation system.

Data Availability
Te data used to support the fndings of this study are available from the corresponding author upon request.

Conflicts of Interest
Te authors declare that they have no conficts of interest.